import java.lang.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.text.*;
import java.text.*;

/**
 * Component: JMeter
 * 
 * @version 2.0 22 Nov 1999
 * @author Raymond Li
 * 
 * <b>Description:</b>
 *		Displays numbers in a textbox with correct decimal format.  Target user cannot
 *		modify the component.  Behaves exactly like a JTextField, except the setText()
 *		method has been disabled.
 * 
 * <b>Constructors:</b>
 *		public JMeter()
 *		public JMeter( Color bg, Color fg )
 *		public JMeter( int leftAccuracy, int rightAccuracy, Color bg, Color fg )
 * 
 *		Each one allows the developer more and more control over the charateristics
 *		of the JMeter object.
 * 
 * <b>Usage:</b>
 *		The setValue( n ) function has been over-loaded to accept multiple data
 *		types.  int, short, double, and long are all accepted and displayed
 *		according to the attributes given in left and right accuracy.
 * 
 * <b>Details:</b>
 *		The component will automatically redraw itself when the left and right
 *		accuracies are mutated.  If the number currently in the JMeter field has too
 *		many digits to the left of the decimal place after the left accuracy
 *		attribute has been modified, the number will not be displayed.  However, this
 *		is not true for the digits to the right.  They will merely be rounded to the
 *		correct decimal place.
 */

public class JMeter extends JTextField
{
	private int fLeftAccuracy;		// number of digit accuracy to left of decimal
	private int fRightAccuracy;		// number of digit accuracy to right of decimal

	/**
	 * Constants used throughout the class to promote flexibility if need be.
	 */
	
	private static final int DEFAULT_COLUMNS = 5;
	private static final int DEFAULT_LEFT_ACCURACY = 1;
	private static final int DEFAULT_RIGHT_ACCURACY = 0;
	private static final int DEFAULT_COLUMN_OFFSET = 2;
	private static final Color DEFAULT_BG = Color.black;
	private static final Color DEFAULT_FG = Color.green;
	private static final int LEADING = 0;
	private static final int TRAILING = 1;

	/**
	 * Default constructor (parameter-less).
	 */
	
	public JMeter()
	{
		super();

		this.setBackground( DEFAULT_BG );
		this.setForeground( DEFAULT_FG );

		this.fLeftAccuracy = DEFAULT_LEFT_ACCURACY;
		this.fRightAccuracy = DEFAULT_RIGHT_ACCURACY;

		Init();
	}

	/**
	 * Constructor with user-defined background and foreground.
	 * 
	 * @param bg initial background color
	 * @param fg initial foreground color, color of text
	 */
	
	public JMeter( Color bg, Color fg )
	{
		super();

		this.setBackground( bg );
		this.setForeground( fg );

		this.fLeftAccuracy = DEFAULT_LEFT_ACCURACY;
		this.fRightAccuracy = DEFAULT_RIGHT_ACCURACY;

		Init();
	}

	/**
	 * Constructor with user-defined left and right of decimal accuracy.
	 * 
	 * @param leftAccuracy accuracy of digits to the left of decimal
	 * @param rightAccuracy accuracy of digits to the right of decimal
	 */
	
	public JMeter( int leftAccuracy, int rightAccuracy )
	{
		super();

		this.setBackground( DEFAULT_BG );
		this.setForeground( DEFAULT_FG );

		this.fLeftAccuracy = leftAccuracy;
		this.fRightAccuracy = rightAccuracy;

		Init();
	}

	/**
	 * Constructor with user-defined accuracy and colors.
	 * 
	 * @param leftAccuracy accuracy of digits to the left of decimal
	 * @param rightAccuracy accuracy of digits to the right of decimal
	 * @param bg initial background color
	 * @param fg initial foreground color, color of text
	 */
	
	public JMeter( int leftAccuracy, int rightAccuracy, Color bg, Color fg )
	{
		super();

		this.setBackground( bg );
		this.setForeground( fg );

		this.fLeftAccuracy = leftAccuracy;
		this.fRightAccuracy = rightAccuracy;

		Init();
	}

	/**
	 * Initializations common to all constructors.
	 */
	
	protected void Init()
	{
		this.setHorizontalAlignment( JTextField.CENTER );
		resetMeter();
	}

	/**
	 * Accessor for number left accuracy.
	 * 
	 * @return the maximum number of digits to left of decimal
	 */
	
	public int getLeftAccuracy() {
		return this.fLeftAccuracy;
	}

	/**
	 * Accessor for right accuracy.
	 * 
	 * @return the maximum number of digits to right of decimal
	 */
	
	public int getRightAccuracy() {
		return this.fRightAccuracy;
	}

	/**
	 * Mutator for left accuracy.
	 */
	
	public void setLeftAccuracy( int n )
	{
		// Make sure there is at least one left of the decimal digit.
		
		if ( n >= 1 )
		{
			this.fLeftAccuracy = n;
			redrawMeter();
		}
	}

	/**
	 * Mutator for left accuracy.
	 */
	
	public void setRightAccuracy( int n )
	{
		/**
		 * The digits to the right of the decimal should not exceed 10 or be
		 * less than 0.
		 */
		
		if ( n >= 0 && n <= 10 )
		{
			this.fRightAccuracy = n;
			redrawMeter();
		}
	}

	/**
	 * Disabled for safety purposes.
	 */
	
	public void setText( String s )
	{ }

	/**
	 * Set the value of the meter using data of type <b>short</b>.
	 */
	
	public void setValue( short num )
	{
		this.setValue( (double) num );
	}

	/**
	 * Set the value of the meter using data of type <b>int</b>.
	 */
	
	public void setValue( int num )
	{
		this.setValue( (double) num );
	}

	/**
	 * Set the value of the meter using data of type <b>long</b>.
	 */
	
	public void setValue( long num )
	{
		this.setValue( (double) num );
	}

	/**
	 * Set the value of the meter using data of type <b>double</b>.
	 */
	
	public void setValue( double num )
	{
		String strTotalAccuracy;
		String strRightAccuracy = Integer.toString( this.fRightAccuracy );
		String formatString;
		String ret;
		
		strTotalAccuracy = Integer.toString( this.fLeftAccuracy + this.fRightAccuracy + 1 );
		formatString = "%0" + strTotalAccuracy + "." + strRightAccuracy + "f";			
		
		Format fmt = new Format( formatString );
		ret = fmt.format( num );

		if ( this.fRightAccuracy == 0 )
			ret = ret.substring( 0, ret.length() - 1 );

		super.setText( ret );
	}

	/**
	 * Meter is zero'ed.
	 */
	
	public void resetMeter ()
	{
		/**
		 * Creating default string to place into Meter.
		 */

		this.setColumns( this.fLeftAccuracy + this.fRightAccuracy + DEFAULT_COLUMN_OFFSET );
		this.validate();
		
		this.setValue( 0 );
	}
	
	/**
	 * Redraws the meter.  When the user changes the accuracy of the number being displayed,
	 * the TextField (view) as well as the text inside must be re-calculated.
	 * 
	 * This is basically the same code as the setValue() method, except due to changes in
	 * the left and/or right accuracy, the textfield needs to be resized.
	 */
	
	public void redrawMeter()
	{
		/*
		String strTotalAccuracy;
		String strRightAccuracy = Integer.toString( this.fRightAccuracy );
		String formatString;
		
		strTotalAccuracy = Integer.toString( this.fLeftAccuracy + this.fRightAccuracy + 1 );
		formatString = "%0" + strTotalAccuracy + "." + strRightAccuracy + "f";			
		
		Format fmt = new Format( formatString );
		super.setText( fmt.format( Double.parseDouble( this.getText() ) ) );
		*/

		this.setValue( Double.parseDouble( this.getText() ) );
		this.setColumns( this.fLeftAccuracy + this.fRightAccuracy + DEFAULT_COLUMN_OFFSET );
		this.validate();
	}
	
	/**
	 * Disallows special key input.
	 */
	
	protected void processComponentKeyEvent(KeyEvent event)	{
		event.consume();
	}
	
	/**
	 * Disallows normal user input.
	 */
	
	protected void processInputMethodEvent( InputMethodEvent event )
	{		event.consume();	}
}